Targeting behaviors to successfully obtain rewards is an essential aspect of survival. In order to execute goal-directed behaviors, organisms must integrate information about their environment into motivated actions. However, in humans, unnatural rewards such as drugs of abuse can often come to take the place of natural rewards, leading to aberrant motivational processing. The performance of these goal-directed behaviors likely involves the concerted activation of specific brain regions and neurotransmitter systems. The nucleus accumbens (NAc) and its dopaminergic inputs form a key brain circuit for processing the reinforcing aspects of both natural and drug rewards. This proposal seeks to examine neurochemical activity in the NAc during the execution of goal-directed behaviors. Fast-scan cyclic voltammetry (FSCV) will be employed to measure changes in sub-second dopamine release in the NAc during a self-administration task for both sucrose and cocaine. Additionally, FSCV will be used to examine alterations in dopamine signaling following abstinence from cocaine self-administration. The results of these studies will provide insight into the factors influencing neurochemical signaling during the pursuit of natural as well as drug rewards. PUBLIC HEALTH RELEVANCE: Drug addiction is a pervasive public health issue for both individuals and their communities. Often, addicts are able to abstain from drug use for extended periods of time, only to relapse after encountering environments or situations previously associated with drug taking. This proposal seeks to examine the neurochemical factors mediating drug seeking behaviors, with a specific emphasis on the role of drug abstinence, and, therefore, will provide key information for the development of pharmacological treatments for drug addiction in humans.